Fundamental of Coal Petrology

Origin of Peat (Peat)The coal is generally derived from peat (peat) deposits in a swamp. Important factors in the formation of peat:

Evolution of Flora DevelopmentThe oldest coal-old from Michigan Central Hurorian derived from algae and fungi. While in the Lower and Upper Devonian era, mostly from coal Psilophites (spt: Taeniocrada decheniana (lower Devonian)). Most of the coal from this era had an average of a thin layer (3-4m) and have no economic value. In Carbon Up, plant start up high until it reaches an altitude of more than 30m but not seberagam now. In this era dominated by: Lepidodendron, Sigillaria, Leginopteris oldhamia, Calamitea. Age of the Upper Carboniferous period known as bituminous coal. Perm important layer of coal was found in the USSR, the dominant form of Gymnosperm cordaites. In the Mesozoic era mainly Jurassic and Lower Cretaceous, Gymnosperm (Ginkcophyta, Cycadophyta and Cornifers) is an important shaper of coal plants, especially in Siberia and Central Asia. In the old swamp and Upper Cretaceous Tertiary Angiosperm plants grow rapidly in N. America, Europe, Japan and Australia. When compared with the Carbon plant at the time, plants in the Mesozoic era, especially the Tertiary era more diverse and specific, and produces a thick peat deposits and diverse in type fasiesnya. The development and evolution will affect the diversity of flora and type of coal produced.


ClimateIn a warmer climate and wet plants grow faster and diverse. Layers of Carbon-old coal-rich Upper Cretaceous and Early Tertiary Top deposited in this climate. However, in the southern Hemisphere and Siberia there are also rich deposits of coal which diendapakan in moderate to cold climates, for example coal-post glacial inter PermoCarbon Gondwana (from Ganganopteris glossopteris) and Permian and Jurassic age coal of the Lower Angara konitnen. Coal layer is deposited in a warm and wet climate is usually lighter and thicker than that deposited in wet climates.

Tectonic and paleogeographic RequirementsLayer formation depends on the relationships and structures on the regional paleogeographic sedimentation. Formation of peat (peat) occur in the depressed area surface and surface water requires a relatively fixed throughout the year above or at least equal to the soil surface. This condition appears in many areas where a lot of flat coastal swamps associated with persisir beach. Besides the swamp also appeared on land (shore or Inland lakes). Depending on the original position of its geography, paralic coal deposit (sea coast) and limnic (Inland) is different.

Coal Paralic Swampy has few trees or no trees and formed outside the distal margin of the delta. Formation is the result of regression and transgression of sea water. Many large coastal Swampy growing under the protection of sand bars and pits that can produce thick deposits of coal.

Back samps natural levee formed behind the great river. At the back Swampy, peats (peat) is rich in mineral matter from flooding that often occurs. Peat deposits can only be preserved in the subsidence area. As a result, many coal-rich sediments associated with this area, as it often appears in the foredeep on a big mountain folds.

Sequence of thick sediment, where in it there is a thin layer of coal (<2m) with a large spread and the presence of marine intercalation is characteristic of the coal bed which was deposited in foredeeps of a large mountain folds. Cyclothem is looping between Inorganic sediment and peat with this sequence is often repeated.

In backdeeps part of a huge mountain folds, subsidence usually fewer and fewer number of layers of coal. When paralic coals deposited in foredeeps, most limnic coals deposited in a large continental basin. Limnic coals have character: formed in a continental graben, the number of layers slightly but each layer is very thick.

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